Preclinical Evaluation of a Modular Inner-Branched Stent Graft to Reconstruct the Left Subclavian Artery in Thoracic Endovascular Aortic Repair: Experimental Study in Pigs

In approximate 40% of thoracic endovascular aortic repair (TEVAR) procedures, the left subclavian artery (LSA) needs to be covered to obtain sufficient proximal sealing zone. To preserve the LSA during the TEVAR for type B aortic dissection (TBAD) adjacent to LSA, our team designed a modular single inner-branched stent graft. This study was performed to evaluate the safety and feasibility of deploying a modular single inner-branched stent graft in a porcine model.Modular inner-branched stent grafts were implanted in 14 pigs via right femoral and right carotid arterial access. Computed tomography angiography (CTA) and angiography were performed in all pigs to appraise the morphological characteristics of the stent grafts at the end of follow-up. The pigs were then euthanized, and tissues were collected for gross and histological examination.The technical success rate was 100% (14/14). One pig suddenly died 5 hours after operation, and 1 pig died after completing the follow-up CTA. During the follow-up period, all surviving pigs showed good mental state, normal diets and activities. Computed tomography angiography examinations showed that all stent grafts were intact without fracture. All bridging covered stents were patent. Angiography showed that the position, shape, and adhesion of the stent grafts were good, and no obvious endoleaks were found. Histological examination showed that the biocompatibility of the stent grafts was good.This study's outcomes demonstrate that it is safe and feasible to deploy a modular single inner-branched stent graft in a porcine model.This device is the first modular device designed to treat TBAD adjacent to LSA in China. This device is a modular two-component system consisting of a thoracic aortic stent graft with a retrograde inner branch and a bridging covered stent. The modular design and the retrograde inner branch are the two important innovations of this device. Theoretically, the device could make it easier and safer for clinicians to treat TBAD adjacent to the LSA.